CN214622638U - Natural gas hydrate exploitation simulation and sand production and prevention experimental device - Google Patents
Natural gas hydrate exploitation simulation and sand production and prevention experimental device Download PDFInfo
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- CN214622638U CN214622638U CN202120962719.9U CN202120962719U CN214622638U CN 214622638 U CN214622638 U CN 214622638U CN 202120962719 U CN202120962719 U CN 202120962719U CN 214622638 U CN214622638 U CN 214622638U
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Abstract
The utility model relates to a geotechnical experiment technical field especially relates to a natural gas hydrate exploitation simulation and go out sand, sand control experimental apparatus. Comprises a reaction kettle and a sand producing and preventing device; a plurality of reaction kettle mining holes are formed in the side wall of the reaction kettle and the lower bottom of the reaction kettle; a plurality of air inlets are also arranged on the lower bottom of the reaction kettle and are uniformly distributed; the first mining steel pipe and the second mining steel pipe penetrate into the reaction kettle through corresponding mining holes of the reaction kettle, and the mining of a horizontal well and a vertical well can be simulated; and the unused mining hole of the reaction kettle is blocked by using a bolt. The utility model discloses hydrate exploitation simulation under the multiple mode of operation can be carried out to can carry out experimental analysis to the sand production characteristic, the sand control measure of exploitation in-process.
Description
Technical Field
The utility model relates to a geotechnical experiment technical field especially relates to a natural gas hydrate exploitation simulation and go out sand, sand control experimental apparatus.
Background
Natural gas hydrate (also called as combustible ice) is made up of water and natural gas (mainly CH)4) Crystalline materials formed in low temperature and high pressure environments are widely distributed in deep sea formations and land permafrost zones. As a novel energy source with high energy density, small environmental pollution and wide distribution, the hydrate is closely concerned by countries in the world. The development prospect of hydrate resources is mainly controlled by the exploitation technical conditions and the development cost, so that a reasonable exploitation mode is selected by combining reservoir characteristics on the basis of actual engineering geological conditions. The existing hydrate exploitation methods mainly comprise heat shock, pressure reduction, chemical reagents, carbon dioxide replacement and the like. Although the exploitation methods are different, the essence of hydrate exploitation is hydrate decomposition, gas is continuously produced in the decomposition process, the pore pressure is continuously increased, and a series of geomechanical problems (such as borehole wall instability, seabed landslide, seabed debris flow and the like) are generated. Therefore, before actual exploitation, the simulation research of the hydrate, particularly the research of the exploitation method and the decomposition gas production rule, has very important engineering significance.
In addition, in the actual hydrate exploitation process, as the hydrate exploitation goes deep, the particle migration, namely the sand production problem, inevitably occurs. Once sand production occurs, the gas production efficiency is greatly reduced, and a serious safety problem is caused. Hydrate pilot mining developed worldwide at present is troubled by the problem of sand production to different extents, for example, two hydrate pilot mining developed in Japan are forced to terminate mining in advance due to the problem of sand production. Therefore, research on the sand production problem in the hydrate exploitation process needs to be developed, and especially effective sand control measures need to be provided to further assist the industrialization process of hydrate resources.
Because of the severe condition of stable existence of the hydrate, the experimental device which can be used for the exploitation simulation of the natural gas hydrate and the research of sand production and prevention at the present stage is very deficient. With the development of the mining technology, various horizontal wells and multi-well combined operation modes appear successively on the basis of a single vertical well, but indoor research aiming at diversified mining modes is quite rare; in addition, the research on sand production and prevention around the mining mode is also slightly insufficient, and especially the comprehensive sand prevention measures combining the conventional sand prevention screen and the sand prevention gravel filtering layer are not reported yet. On the basis, the correlation among the type of the hydrate reservoir, the exploitation state, the sand production rule and the sand prevention measures needs to be further studied.
SUMMERY OF THE UTILITY MODEL
The to-be-solved technical problem of the utility model is that because the harsh condition of hydrate stable occurrence, the experimental apparatus that can be used to the simulation of natural gas hydrate exploitation and go out sand, sand control research in the present stage is very deficient.
For solving the technical problem, the utility model relates to a natural gas hydrate exploitation simulation and sand production, sand control experimental apparatus can develop the hydrate exploitation simulation under the multiple operation mode to can carry out experimental analysis to the sand production characteristic, the sand control measure of exploitation in-process.
In order to achieve the above object, the utility model discloses specifically realize through following technical scheme:
a natural gas hydrate exploitation simulation and sand production and prevention experimental device comprises a reaction kettle and a sand production and prevention device; the reaction kettle is connected with the upper cover of the reaction kettle and the lower bottom of the reaction kettle through bolts and nuts; the side wall of the reaction kettle and the bottom of the reaction kettle are provided with a plurality of reaction kettle mining holes to meet the simulation of multi-well mining, in the embodiment, the side wall of the reaction kettle is provided with 2 reaction kettle mining holes, the bottom of the reaction kettle is provided with 3 reaction kettle mining holes, and the number of the reaction kettle mining holes can be set according to actual needs; the lower bottom of the reaction kettle is also provided with a plurality of air inlets which are uniformly distributed to ensure uniform air inlet, the air inlets are connected with a gas supply device to provide high-pressure gas into the reaction kettle, in the embodiment, the number of the air inlets is 4, and two adjacent air inlets are arranged at an angle of 90 degrees; the first mining steel pipe and the second mining steel pipe penetrate into the reaction kettle through corresponding mining holes of the reaction kettle, and the mining of a horizontal well and a vertical well can be simulated; plugging unused mining holes of the reaction kettle by using bolts;
the reaction kettle, the upper cover of the reaction kettle and the lower bottom of the reaction kettle form a whole body which is positioned on the bracket and is connected with the bracket through a rotating shaft on the outer side wall; the bracket consists of a bracket upright and a bracket base, and the bracket upright and the bracket base integrally form a triangular structure; the motor drives the rotating shaft to rotate, so that the reaction kettle, the upper cover of the reaction kettle and the lower bottom of the reaction kettle are integrally rotated, and hydrate exploitation simulation of a horizontal well, a vertical well and an inclined well can be realized; meanwhile, the bracket is provided with a limiter for locking the rotation state;
a shaft pressure controller is connected below the upper cover of the reaction kettle, a telescopic shaft is connected below the shaft pressure controller, the shaft pressure controller is composed of a servo motor and can control the length of the telescopic shaft, a pressure plate is connected below the telescopic shaft, and the pressure plate applies pressure to an experimental sand sample to simulate the overlying pressure born by an actual hydrate; sealing rings are arranged on the upper cover of the reaction kettle, the pressure plate and the lower bottom of the reaction kettle to realize environmental sealing; meanwhile, the reaction kettle base is also provided with a reaction kettle mining hole, the reaction kettle is rotated by 180 degrees, and the pressurized mining simulation of the vertical shaft can be realized.
Further, the first production steel pipe is completely the same as the second production steel pipe; one end of the first mining steel pipe and one end of the second mining steel pipe are connected with the sand storage drying box, the other ends of the first mining steel pipe and the second mining steel pipe are connected with the sand prevention inner net and the sand prevention outer net, and the ends connected with the sand prevention inner net and the sand prevention outer net are positioned in the reaction kettle; the flexible telescopic rods are arranged at the end parts of the first mining steel pipe and the second mining steel pipe in the reaction kettle, the diameter of each flexible telescopic rod is slightly smaller than that of the first mining steel pipe and the second mining steel pipe, the flexible telescopic rods are sleeved at the end parts of the mining steel pipes in a clearance mode, and can stretch and retract to push sand particles in the first mining steel pipe and the second mining steel pipe to the sand storage drying box; sand particles generated by the decomposition of the hydrate are stored and dried in the sand storage drying box, and the sand storage drying box can dry the sand particles to further determine the moisture quality; the sand storage drying box is positioned on the second balance, so that the mass change of sand particles in the sand storage drying box can be acquired in real time; the air compressor is connected with the first mining steel pipe and the second mining steel pipe.
Furthermore, the sand control inner net is integrally cylindrical and rectangular after being unfolded, the diameter of the sand control inner net is the same as that of the first mining steel pipe and the second mining steel pipe, and the sand control inner net is connected with the first mining steel pipe and the second mining steel pipe; the sand-proof outer net is cylindrical and is sleeved outside the sand-proof inner net; gravel is filled between the sand prevention inner net and the sand prevention outer net to form a sand prevention gravel layer; the sand control intranet is the resistance net with the sand control outer net, and the sand control intranet has resistance heating function with the sand control outer net when acting as the sand control screen cloth effect, and the sand control intranet can produce the heat with the sand control outer net under the circular telegram circumstances promptly, makes temperature rising in the reation kettle, and the simulation is exploited the well heat shock method and is exploited the hydrate. The sand control screen is combined with the sand control gravel layer, the interaction relation between the sand control screen and the sand control gravel layer and the sand production of the hydrate reservoir can be explored aiming at different hydrate reservoirs, and a comprehensive sand control measure combining the sand control screen and the sand control gravel layer is further provided.
Furthermore, the sand control inner net and the sand control outer net are provided with a plurality of temperature sensors and a plurality of pressure sensors, the temperature sensors are arranged on two sides of the sand control outer net, and the pressure sensors are arranged on the sand control inner net and the sand control outer net and are mainly used for acquiring the pressure of the sand control inner net and the sand control outer net, namely the internal pressure and the external pressure of the sand control gravel layer, so that the permeability change rule of the sand control gravel layer in the experimental process can be further acquired; the temperature sensor and the pressure sensor are connected with the computer to acquire the pressure and the temperature in the reaction kettle in real time, so that the permeability evolution rule of the sand prevention gravel layer in the hydrate decomposition process can be further acquired, and the method is very important for evaluating the sand prevention effect of the sand prevention gravel layer and selecting the optimal sand prevention gravel level.
Further, electrode holders are arranged on the periphery of the reaction kettle, electrodes are arranged on the electrode holders, the number of the electrode holders is 6, the adjacent electrode holders are arranged at an angle of 60 degrees, and each group of the electrode holders is provided with 8 electrodes from bottom to top; the electrode can acquire voltage signals in the whole reaction kettle in real time, the distribution form of the hydrate is acquired in real time through a resistivity tomography technology, and the decomposition evolution process of the hydrate is dynamically analyzed in the hydrate exploitation process.
Further, the gas supply device comprises a methane gas cylinder, the methane gas cylinder is connected with a gas pressure controller through a pressure regulating valve and a methane gas storage tank, the gas pressure controller is connected with the reaction kettle through a gas inlet hole, and high-pressure gas is supplied to the reaction kettle to synthesize hydrate; the water storage tank is connected with the gas-liquid separator and used for storing part of water generated by hydrate decomposition, and the water storage tank is placed above the first level to obtain quality change in real time; the gas storage tank is connected with the gas-liquid separator through a gas flowmeter and used for storing methane gas generated by hydrate decomposition, and the gas flowmeter acquires the volume of the gas in real time; the gas-liquid separator is connected with a back pressure valve, the back pressure valve is connected with the first mining steel pipe and the second mining steel pipe, and the back pressure valve can realize pressure regulation; the vacuum pump is connected with the gas flowmeter, and can realize the vacuum state in the pipeline and the reaction kettle.
Furthermore, the first valve, the second valve, the third valve, the fourth valve, the fifth valve, the sixth valve, the seventh valve, the eighth valve, the ninth valve, the tenth valve, the eleventh valve, the twelfth valve, the thirteenth valve, the fourteenth valve, the fifteenth valve and the sixteenth valve realize the opening and closing of each pipeline; the gas pressure controller, the gas flowmeter, the first balance, the second balance, the shaft pressure controller, the telescopic shaft, the pressure sensor and the temperature sensor are all connected with the computer, and real-time recording of data can be achieved.
Furthermore, the whole body formed by the upper cover of the reaction kettle, the reaction kettle and the lower bottom of the reaction kettle is positioned in a constant-temperature gas bath, and the constant-temperature gas bath provides a low-temperature environment required by synthesis of hydrate.
The natural gas hydrate exploitation simulation and sand production and prevention experimental method corresponding to the device mainly comprises the following steps:
s1 airtightness test
And ventilating all pipelines of the whole experimental system to finish the air tightness inspection.
S2 production of natural gas hydrate
The method mainly comprises the following steps:
firstly, according to the experimental purpose, dry sand with specific gradation is prepared, a certain amount of deionized water is prepared according to the saturation of hydrate, and the dry sand and the deionized water are fully mixed to form a mixed sand sample.
Secondly, putting the mixed sand sample into a reaction kettle, adjusting the length of a telescopic shaft by adopting a shaft pressure controller, and compacting the mixed sand sample through a pressure plate; if the overburden pressure is not to be simulated for the mining process, the pressure plate is raised and if the overburden pressure is to be simulated for the mining process, the blending pattern is further compacted by applying a specified pressure through the axle pressure controller.
And thirdly, opening the vacuum pump, and pumping out air in the reaction kettle through the vacuum pump.
And fourthly, introducing methane gas into the reaction kettle, so that the methane gas is fully mixed with the mixed sand sample, and the gas pressure controller provides a high-pressure environment required by hydrate synthesis.
Reducing the ambient temperature in the whole reaction kettle through a constant-temperature air bath to finally form a temperature and pressure environment required by synthesis of hydrate; at this time, hydrate synthesis was started, and the gas pressure was kept substantially constant while continuing methane gas supply, and it was considered that hydrate synthesis was completed.
S3 mining simulation
The exploitation simulation process can adopt a heat shock method or a depressurization method according to needs, and each method is divided into exploitation well area simulation and reaction kettle integral simulation.
When a depressurization method is adopted, the pressure of a back pressure valve is reduced in the area simulation of the mining well, so that the hydrate is partially decomposed in the first mining steel pipe area and the second mining steel pipe area; the integral simulation of the reaction kettle needs a back pressure valve and a gas pressure controller to be used jointly, the gas pressure controller reduces the pressure of the integral reaction kettle, so that hydrates in the reaction kettle are integrally decomposed, and the pressure of the back pressure valve is lower than the gas pressure in the reaction kettle, so that the hydrates are output from the first mining steel pipe and the second mining steel pipe.
When a thermal shock method is adopted, the mining well area simulation is that the temperature of areas near the sand prevention inner net and the sand prevention outer net is raised and the hydrate is partially decomposed by carrying out resistance heating on the sand prevention inner net and the sand prevention outer net; the integral decomposition of the reaction kettle raises the integral temperature of the reaction kettle through a constant-temperature gas bath, and the hydrate is integrally decomposed in a large range.
S4, yield collection
First collection
And respectively collecting methane gas, water and sand particles generated by the decomposition of the hydrate. Methane gas and part of water generated by decomposition respectively enter a gas storage tank and a water storage tank through a gas-liquid separator; the sand particles and part of water generated by separation exist in the first mining steel pipe and the second mining steel pipe, and the sand particles and the water existing in the first mining steel pipe and the second mining steel pipe are pushed to the sand storage drying box through the flexible telescopic rod.
② secondary collection
After primary collection, starting a vacuum pump, further collecting the residual methane gas to a gas storage tank, wherein a gas volume can be obtained by a gas flowmeter; after the gas secondary collection is finished, the air compressor is started, and the air compressor can further blow and sweep the sand particles remained in the first mining steel pipe and the second mining steel pipe to the sand storage drying box.
S5, repeat experiment (Sand control experiment)
According to the experimental requirements, the specifications (different apertures, lengths and the like) of the sand-prevention inner net, the sand-prevention outer net, the mixed sand sample, the grading of the sand-prevention gravel layer, the particle composition and the like are adjusted, and the experimental steps are repeated.
Analysis of the results S6
The experimental result analysis comprises analysis of hydrate decomposition gas production rule, sand production characteristic, sand prevention measure, hydrate generation decomposition dynamic evolution and the like.
Analysis of gas production by decomposition
The whole experimental process records the related data of methane gas volume, moisture quality, temperature, pressure and the like in the hydrate decomposition process, so that the relationship between the gas production rate and the specific temperature and pressure environment in the local mining and overall mining modes can be obtained, and the decomposition gas production rule under the heat shock and pressure reduction mining method can be obtained.
Analysis of sand production characteristics
After each experiment is finished, the reaction kettle, the upper cover of the reaction kettle and the lower bottom of the reaction kettle are detached, and the experimental sand sample in the reaction kettle is subjected to comparative analysis before and after the experiment, including analysis on the particle size change of the sand sample and morphological evolution of the whole sand sample; taking out sand grains in the sand storage drying box, and analyzing the grain size of the sand grains; and detaching the inner sand prevention net and the outer sand prevention net, and analyzing the particle size of the residual sand particles in the sand prevention gravel layer.
Analysis of sand control measures
And developing hydrate decomposition simulation experiments under different sand prevention inner nets, sand prevention outer nets and sand prevention gravel layers, analyzing sand production characteristics, obtaining sand prevention effects of the different sand prevention inner nets, the different sand prevention outer nets and the different sand prevention gravel layers (performing key analysis on permeability evolution rules of the sand prevention gravel layers in the experiment process), and providing sand prevention measures aiming at different hydrate reservoirs.
Analysis of dynamic evolution of hydrate formation and decomposition
By means of the chromatographic imaging technology, the resistivity distribution image of the whole sample in the reaction kettle can be obtained through the electrode outside the reaction kettle, the hydrate distribution condition is visually presented, and dynamic evolution analysis of the hydrate generation and decomposition process is carried out.
Compared with the prior art, the utility model has the advantages of it is following:
(1) and multi-well combined mining simulation can be realized. The utility model discloses well reation kettle is provided with a plurality of reation kettle exploitation holes, can jointly exploit single pit shaft or multiwell according to the experiment needs and simulate.
(2) The simulation method can simulate multi-well cylindrical modes such as horizontal wells, vertical wells, inclined wells and the like. Because the utility model discloses a reation kettle wholly sets up on the support, is provided with the rotation axis simultaneously, can realize the simulation of arbitrary angle pit shaft.
(3) A simulation may be performed on the overburden. The utility model can apply overlying pressure to the sample through the axial pressure controller, the telescopic shaft and the pressure plate, and is used for simulating the overlying rock stratum and seawater pressure born when the actual hydrate occurs; meanwhile, the reaction kettle base is also provided with a reaction kettle mining hole, the reaction kettle is rotated by 180 degrees, and the pressurized mining simulation of the vertical shaft can be realized.
(4) The experimental research can be carried out on different mining methods and decomposition ranges. The utility model discloses can simulate heat shock and step-down exploitation, on this basis, to heat shock and step-down exploitation, the utility model discloses all can realize exploiting the regional small scale hydrate of pit shaft and decompose and whole reation kettle is the corresponding simulation that hydrate decomposed on a large scale.
(5) The utility model discloses combine together sand control net and sand control gravel layer, to different hydrate reservoir beds, can probe into the interact relation between sand control screen cloth and sand control gravel layer and the hydrate reservoir bed goes out the sand, further provide the comprehensive sand control measure that sand control net and sand control gravel layer combined together.
(6) The utility model discloses a set up pressure sensor respectively at sand control intranet and sand control outer net, can further obtain the permeability evolution law of sand control gravel layer at hydrate decomposition in-process, this is very important to evaluation sand control gravel layer sand control effect and select optimum sand control gravel level.
(7) The utility model discloses be provided with a plurality of electrodes at the reation kettle outer wall, can acquire the inside hydrate distribution condition of reation kettle with the help of resistivity distribution image, generate and decompose the process and carry out dynamic evolution analysis to the hydrate.
(8) After decomposing to the hydrate, gas and sand granule are difficult to collect complete problem, the utility model discloses an increase air compressor machine, flexible telescopic link isotructure, realize the first secondary collection on the basis of collecting, further improved the experiment precision.
(9) The whole reaction kettle is a detachable device, and the comparative analysis of particle size and whole form can be carried out on samples before and after the experiment.
Drawings
FIG. 1 is a schematic view of the overall structure of the present invention;
FIG. 2 is a schematic diagram of the distribution of temperature sensors and pressure sensors;
FIG. 3 is a schematic structural view of the first mining steel pipe after the sand control inner net and the sand control outer net are unfolded;
FIG. 4 is a front view of the bracket;
FIG. 5 is a side view of the bracket;
fig. 6 is a schematic view of shaft mining;
FIG. 7 is an electrode distribution diagram;
FIG. 8 is a view of the electrode holder distribution;
FIG. 9 is a layout of air inlets, mining holes of a reaction kettle, and bolts and nuts.
In the figure, a methane gas bottle 1, a pressure regulating valve 2, a first valve 3-1, a second valve 3-2, a third valve 3-3, a fourth valve 3-4, a fifth valve 3-5, a sixth valve 3-6, a seventh valve 3-7, an eighth valve 3-8, a ninth valve 3-9, a tenth valve 3-10, an eleventh valve 3-11, a twelfth valve 3-12, a thirteenth valve 3-13, a fourteenth valve 3-14, a fifteenth valve 3-15, a sixteenth valve 3-16, a methane gas storage tank 4, a gas pressure controller 5, an air compressor 6, a vacuum pump 7, a gas flow meter 8, a gas-liquid separator 9, a back pressure valve 10, a gas storage tank 11, a water storage tank 12, a first day flat 13, a first mining steel pipe 14, a second mining steel pipe 15, the device comprises a sand storage drying box 16, a second balance 17, a computer 18, a reaction kettle upper cover 19, bolts 20, a sealing ring 21, a shaft pressure controller 22, a telescopic shaft 23, a pressure plate 24, a reaction kettle 25, a sand prevention outer net 26, a sand prevention inner net 27, a reaction kettle mining hole 28, a sand prevention gravel layer 29, a flexible telescopic rod 30, nuts 31, air inlet holes 32, a reaction kettle lower bottom 33, a constant temperature air bath 34, a pressure sensor 35, a temperature sensor 36, a limiter 37, a motor 38, a support upright rod 39, a support base 40, a rotating shaft 41, an electrode seat 42 and an electrode 43.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, embodiments of the present invention are combined to clearly and completely describe the technical solutions in the embodiments of the present invention. It is to be understood that the embodiments described are only some of the embodiments of the present invention, and not all of them. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
Example 1:
a natural gas hydrate exploitation simulation and sand production and prevention experimental device used for implementing the method of the embodiment 1 comprises a reaction kettle 25 and a sand production and prevention device; as shown in fig. 1, the reaction kettle 25 is connected with the upper reaction kettle cover 19 and the lower reaction kettle bottom 33 through bolts 20 and nuts 31; the side wall of the reaction kettle 25 and the bottom 33 of the reaction kettle are provided with a plurality of reaction kettle mining holes 28 to meet the simulation of multi-well mining, in the embodiment, the side wall of the reaction kettle 25 is provided with 2 reaction kettle mining holes 28, the bottom 33 of the reaction kettle is provided with 3 reaction kettle mining holes 28, and the number of the reaction kettle mining holes 28 can be set according to actual needs; a plurality of air inlets 32 are also arranged on the bottom 33 of the reaction kettle and are uniformly distributed to ensure uniform air inlet, the air inlets 32 are connected with a gas supply device to provide high-pressure gas into the reaction kettle 25, in the embodiment, the number of the air inlets 32 is 4, and two adjacent air inlets 32 are arranged at an angle of 90 degrees; the first mining steel pipe 14 and the second mining steel pipe 15 penetrate into the reaction kettle 25 through corresponding mining holes 28 of the reaction kettle, and the mining of a horizontal well and a vertical well can be simulated; the unused mining holes 28 of the reaction kettle are plugged by using bolts 20;
as shown in fig. 4 and 5, the whole body composed of the reaction kettle 25, the reaction kettle upper cover 19 and the reaction kettle lower bottom 33 is positioned on the bracket and connected with the bracket through the rotating shaft 41 on the outer side wall; the bracket consists of a bracket upright post 39 and a bracket base 40, and the bracket upright post 39 and the bracket base 40 form a triangular structure integrally; the motor 38 drives the rotating shaft 41 to rotate, so that the reaction kettle 25, the reaction kettle upper cover 19 and the reaction kettle lower bottom 33 are integrally rotated, and the hydrate exploitation simulation of a horizontal well, a vertical well and an inclined well can be realized; meanwhile, a limiter 37 is arranged on the bracket and used for locking the rotating state;
a shaft pressure controller 22 is connected below the upper cover 19 of the reaction kettle, a telescopic shaft 23 is connected below the shaft pressure controller 22, the shaft pressure controller 22 is composed of a servo motor and can control the length of the telescopic shaft 23, a pressure plate 24 is connected below the telescopic shaft 23, pressure is applied to the experimental sand sample through the pressure plate 24, and the overlying pressure born by the actual hydrate is simulated; the upper cover 19, the pressure plate 24 and the lower bottom 33 of the reaction kettle are provided with sealing rings 21 to realize environmental sealing; meanwhile, the reaction kettle base is also provided with a reaction kettle mining hole, as shown in fig. 6, the reaction kettle is rotated by 180 degrees, and the pressurized mining simulation of the vertical shaft can be realized.
Example 2:
the first production steel pipe 14 is identical to the second production steel pipe 15; one end of the first mining steel pipe 14 and one end of the second mining steel pipe 15 are connected with the sand storage drying box 16, the other ends of the first mining steel pipe and the second mining steel pipe are connected with the sand control inner net 27 and the sand control outer net 26, and the ends connected with the sand control inner net 27 and the sand control outer net 26 are positioned in the reaction kettle 25; the end parts, located in the reaction kettle 25, of the first mining steel pipe 14 and the second mining steel pipe 15 are provided with flexible telescopic links 30, the diameter of each flexible telescopic link 30 is slightly smaller than that of the first mining steel pipe 14 and the second mining steel pipe 15, the flexible telescopic links 30 are sleeved at the end parts of the mining steel pipes in a clearance mode, the flexible telescopic links 30 can be stretched through hydraulic pressure, and sand particles in the first mining steel pipe 14 and the second mining steel pipe 15 can be pushed to the sand storage drying box 16; sand particles generated by the decomposition of the hydrate are stored and dried in the sand storage drying box 16, and the sand storage drying box 16 can dry the sand particles to further determine the moisture quality; the sand storage drying box 16 is positioned on the second balance 17, and the mass change of sand particles in the sand storage drying box 16 can be acquired in real time; the air compressor 6 is connected with the first mining steel pipe 14 and the second mining steel pipe 15.
Example 3:
as shown in fig. 1 and 3, the sand control inner mesh 27 is cylindrical as a whole, is rectangular after being unfolded, has the same diameter as the first production steel pipe 14 and the second production steel pipe 15, and is connected to the first production steel pipe 14 and the second production steel pipe 15; the sand-proof outer net 26 is cylindrical and is sleeved outside the sand-proof inner net 27; gravel is filled between the sand-prevention inner net 27 and the sand-prevention outer net 26 to form a sand-prevention gravel layer 29; sand control intranet 27 and sand control outer net 26 are the resistance net, and sand control intranet 27 and sand control outer net 26 self have the resistance heating function when acting as the sand control screen cloth effect, and sand control intranet 27 and sand control outer net 26 can produce the heat under the circular telegram circumstances promptly, make temperature rising in reation kettle 25, and the hydrate is mined to the simulation exploitation well heat shock method. The sand control screen is combined with the sand control gravel layer, the interaction relation between the sand control screen and the sand control gravel layer and the sand production of the hydrate reservoir can be explored aiming at different hydrate reservoirs, and a comprehensive sand control measure combining the sand control screen and the sand control gravel layer is further provided.
Example 4:
as shown in fig. 2, a plurality of temperature sensors 36 and a plurality of pressure sensors 35 are disposed on the inner sand prevention mesh 27 and the outer sand prevention mesh 26, the temperature sensors 36 are disposed on both sides of the outer sand prevention mesh 26, and the pressure sensors 35 are disposed on the inner sand prevention mesh 27 and the outer sand prevention mesh 26, and are mainly used for acquiring pressures of the inner sand prevention mesh 27 and the outer sand prevention mesh 26, that is, internal and external pressures of the sand prevention gravel layer 29, so as to further obtain a permeability change rule of the sand prevention gravel layer 29 in an experimental process; the temperature sensor 36 and the pressure sensor 35 are connected with the computer 18 to acquire the pressure and the temperature in the reaction kettle 25 in real time, so that the permeability evolution rule of the sand-proof gravel layer in the hydrate decomposition process can be further acquired, which is very important for evaluating the sand-proof effect of the sand-proof gravel layer and selecting the optimal sand-proof gravel grade.
Example 5:
as shown in fig. 7 and 8, electrode holders 42 are arranged on the periphery of the reaction kettle 25, electrodes 43 are arranged on the electrode holders 42, 6 groups of the electrode holders 42 are arranged, an angle of 60 ° is formed between adjacent electrode holders 42, and 8 electrodes 43 are arranged on each group of the electrode holders 42 from bottom to top; the electrode 43 can acquire the voltage signal in the whole reaction kettle 25 in real time, acquire the distribution form of the hydrate in real time through a resistivity tomography technology, and dynamically analyze the decomposition evolution process of the hydrate in the exploitation process of the hydrate.
Example 6:
as shown in fig. 1, the gas supply device comprises a methane gas cylinder 1, the methane gas cylinder 1 is connected with a gas pressure controller 5 through a pressure regulating valve 2 and a methane gas storage tank 4, the gas pressure controller 5 is connected with the reaction kettle through a gas inlet 32, and high-pressure gas is supplied into the reaction kettle 25 to synthesize hydrate; the water storage tank 12 is connected with the gas-liquid separator 9 and used for storing part of water generated by the decomposition of the hydrate, and the water storage tank 12 is placed on the first balance 13 to obtain the mass change in real time; the gas storage tank 11 is connected with the gas-liquid separator 9 through a gas flowmeter 8 and used for storing methane gas generated by hydrate decomposition, and the gas flowmeter 8 acquires the volume of the gas in real time; the gas-liquid separator 9 is connected with a back pressure valve 10, the back pressure valve 10 is connected with a first mining steel pipe 14 and a second mining steel pipe 15, and the back pressure valve 10 can realize pressure regulation; the vacuum pump 7 is connected with the gas flowmeter 8, and can realize the vacuum state in the pipeline and the reaction kettle 25.
Example 7:
as shown in fig. 1 and 2, the first valve 3-1, the second valve 3-2, the third valve 3-3, the fourth valve 3-4, the fifth valve 3-5, the sixth valve 3-6, the seventh valve 3-7, the eighth valve 3-8, the ninth valve 3-9, the tenth valve 3-10, the eleventh valve 3-11, the twelfth valve 3-12, the thirteenth valve 3-13, the fourteenth valve 3-14, the fifteenth valve 3-15 and the sixteenth valve 3-16 realize the opening and closing of each pipeline; the gas pressure controller 5, the gas flowmeter 8, the first balance 13, the second balance 17, the shaft pressure controller 22, the telescopic shaft 23, the pressure sensor 35 and the temperature sensor 36 are all connected with the computer 18, and real-time recording of data can be achieved.
Example 8:
the whole formed by the upper cover 19 of the reaction kettle, the reaction kettle 25 and the lower bottom 33 of the reaction kettle is positioned in a constant temperature gas bath 34, and the constant temperature gas bath 34 provides a low temperature environment required by synthesizing hydrate.
The natural gas hydrate exploitation simulation and sand production and prevention experimental method by using any one of the devices in the embodiments 1 to 8 mainly comprises the following steps:
s1 airtightness test
And ventilating all pipelines of the whole experimental system to finish the air tightness inspection.
S2 production of natural gas hydrate
The method mainly comprises the following steps:
firstly, according to the experimental purpose, dry sand with specific gradation is prepared, a certain amount of deionized water is prepared according to the saturation of hydrate, and the dry sand and the deionized water are fully mixed to form a mixed sand sample.
Secondly, putting the mixed sand sample into a reaction kettle, adjusting the length of a telescopic shaft by adopting a shaft pressure controller, and compacting the mixed sand sample through a pressure plate; if the overburden pressure is not to be simulated for the mining process, the pressure plate is raised and if the overburden pressure is to be simulated for the mining process, the blending pattern is further compacted by applying a specified pressure through the axle pressure controller.
And thirdly, opening the vacuum pump, and pumping out air in the reaction kettle through the vacuum pump.
And fourthly, introducing methane gas into the reaction kettle, so that the methane gas is fully mixed with the mixed sand sample, and the gas pressure controller provides a high-pressure environment required by hydrate synthesis.
Reducing the ambient temperature in the whole reaction kettle through a constant-temperature air bath to finally form a temperature and pressure environment required by synthesis of hydrate; at this time, hydrate synthesis was started, and the gas pressure was kept substantially constant while continuing methane gas supply, and it was considered that hydrate synthesis was completed.
S3 mining simulation
The exploitation simulation process can adopt a heat shock method or a depressurization method according to needs, and each method is divided into exploitation well area simulation and reaction kettle integral simulation.
When a depressurization method is adopted, the pressure of a back pressure valve is reduced in the area simulation of the mining well, so that the hydrate is partially decomposed in the first mining steel pipe area and the second mining steel pipe area; the integral simulation of the reaction kettle needs a back pressure valve and a gas pressure controller to be used jointly, the gas pressure controller reduces the pressure of the integral reaction kettle, so that hydrates in the reaction kettle are integrally decomposed, and the pressure of the back pressure valve is lower than the gas pressure in the reaction kettle, so that the hydrates are output from the first mining steel pipe and the second mining steel pipe.
When a thermal shock method is adopted, the mining well area simulation is that the temperature of areas near the sand prevention inner net and the sand prevention outer net is raised and the hydrate is partially decomposed by carrying out resistance heating on the sand prevention inner net and the sand prevention outer net; the integral decomposition of the reaction kettle raises the integral temperature of the reaction kettle through a constant-temperature gas bath, and the hydrate is integrally decomposed in a large range.
S4, yield collection
First collection
And respectively collecting methane gas, water and sand particles generated by the decomposition of the hydrate. Methane gas and part of water generated by decomposition respectively enter a gas storage tank and a water storage tank through a gas-liquid separator; the sand particles and part of water generated by separation exist in the first mining steel pipe and the second mining steel pipe, and the sand particles and the water existing in the first mining steel pipe and the second mining steel pipe are pushed to the sand storage drying box through the flexible telescopic rod.
② secondary collection
After primary collection, starting a vacuum pump, further collecting the residual methane gas to a gas storage tank, wherein a gas volume can be obtained by a gas flowmeter; after the gas secondary collection is finished, the air compressor is started, and the air compressor can further blow and sweep the sand particles remained in the first mining steel pipe and the second mining steel pipe to the sand storage drying box.
S5, repeat experiment (Sand control experiment)
According to the experimental requirements, the specifications (different apertures, lengths and the like) of the sand-prevention inner net, the sand-prevention outer net, the mixed sand sample, the grading of the sand-prevention gravel layer, the particle composition and the like are adjusted, and the experimental steps are repeated.
Analysis of the results S6
The experimental result analysis comprises analysis of hydrate decomposition gas production rule, sand production characteristic, sand prevention measure, hydrate generation decomposition dynamic evolution and the like.
Analysis of gas production by decomposition
The whole experimental process records the related data of methane gas volume, moisture quality, temperature, pressure and the like in the hydrate decomposition process, so that the relationship between the gas production rate and the specific temperature and pressure environment in the local mining and overall mining modes can be obtained, and the decomposition gas production rule under the heat shock and pressure reduction mining method can be obtained.
Analysis of sand production characteristics
After each experiment is finished, the reaction kettle, the upper cover of the reaction kettle and the lower bottom of the reaction kettle are detached, and the experimental sand sample in the reaction kettle is subjected to comparative analysis before and after the experiment, including analysis on the particle size change of the sand sample and morphological evolution of the whole sand sample; taking out sand grains in the sand storage drying box, and analyzing the grain size of the sand grains; and detaching the inner sand prevention net and the outer sand prevention net, and analyzing the particle size of the residual sand particles in the sand prevention gravel layer.
Analysis of sand control measures
And developing hydrate decomposition simulation experiments under different sand prevention inner nets, sand prevention outer nets and sand prevention gravel layers, analyzing sand production characteristics, obtaining sand prevention effects of the different sand prevention inner nets, the different sand prevention outer nets and the different sand prevention gravel layers (performing key analysis on permeability evolution rules of the sand prevention gravel layers in the experiment process), and providing sand prevention measures aiming at different hydrate reservoirs.
Analysis of dynamic evolution of hydrate formation and decomposition
By means of the chromatographic imaging technology, the resistivity distribution image of the whole sample in the reaction kettle can be obtained through the electrode outside the reaction kettle, the hydrate distribution condition is visually presented, and dynamic evolution analysis of the hydrate generation and decomposition process is carried out.
In the present specification, each embodiment is described with emphasis on differences from other embodiments, and the same or similar parts between the embodiments may be referred to each other. The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (8)
1. The utility model provides a gas hydrate exploitation simulation and sand production, sand control experimental apparatus which characterized in that: comprises a reaction kettle and a sand producing and preventing device; the reaction kettle is connected with the upper cover of the reaction kettle and the lower bottom of the reaction kettle through bolts and nuts; a plurality of reaction kettle mining holes are formed in the side wall of the reaction kettle and the lower bottom of the reaction kettle; a plurality of air inlets are also arranged on the lower bottom of the reaction kettle and are uniformly distributed, and the air inlets are connected with a gas supply device; the first mining steel pipe and the second mining steel pipe penetrate into the reaction kettle through corresponding mining holes of the reaction kettle; plugging unused mining holes of the reaction kettle by using bolts;
the reaction kettle, the upper cover of the reaction kettle and the lower bottom of the reaction kettle form a whole body which is positioned on the bracket and is connected with the bracket through a rotating shaft on the outer side wall; the bracket consists of a bracket upright and a bracket base, and the bracket upright and the bracket base integrally form a triangular structure; the motor drives the rotating shaft to rotate;
a shaft pressure controller is connected below the upper cover of the reaction kettle, a telescopic shaft is connected below the shaft pressure controller, the shaft pressure controller is composed of a servo motor, and a pressure plate is connected below the telescopic shaft; the upper cover of the reaction kettle, the pressure plate and the lower bottom of the reaction kettle are provided with sealing rings.
2. The assay device of claim 1, wherein: one end of the first mining steel pipe and one end of the second mining steel pipe are connected with the sand storage drying box, the other ends of the first mining steel pipe and the second mining steel pipe are connected with the sand prevention inner net and the sand prevention outer net, and the ends connected with the sand prevention inner net and the sand prevention outer net are positioned in the reaction kettle; the end parts of the first mining steel pipe and the second mining steel pipe in the reaction kettle are provided with flexible telescopic links, and the flexible telescopic links are sleeved at the end parts of the mining steel pipes in a clearance manner; storing and drying sand particles generated by the decomposition of the hydrate in a sand storage drying box; the sand storage drying box is positioned above the second balance; the air compressor is connected with the first mining steel pipe and the second mining steel pipe.
3. The assay device of claim 2, wherein: the sand control inner net is integrally cylindrical, is rectangular after being unfolded, has the same diameter as the first mining steel pipe and the second mining steel pipe, and is connected with the first mining steel pipe and the second mining steel pipe; the sand-proof outer net is cylindrical and is sleeved outside the sand-proof inner net; gravel is filled between the sand prevention inner net and the sand prevention outer net to form a sand prevention gravel layer; the sand prevention inner net and the sand prevention outer net are resistance nets.
4. The assay device of claim 2 or 3, wherein: the sand control inner net and the sand control outer net are provided with a plurality of temperature sensors and a plurality of pressure sensors, the temperature sensors are arranged on two sides of the sand control outer net, and the pressure sensors are arranged on the sand control inner net and the sand control outer net; the temperature sensor and the pressure sensor are both connected with the computer.
5. The assay device of claim 1, wherein: the electrode holders are arranged on the periphery of the reaction kettle, electrodes are arranged on the electrode holders, the number of the electrode holders is 6, the adjacent electrode holders are arranged at an angle of 60 degrees, and each group of the electrode holders are provided with 8 electrodes from bottom to top.
6. The assay device of claim 1, wherein: the gas supply device comprises a methane gas cylinder, the methane gas cylinder is connected with a gas pressure controller through a pressure regulating valve and a methane gas storage tank, and the gas pressure controller is connected with the reaction kettle through a gas inlet hole; the water storage tank is connected with the gas-liquid separator and is placed above the first level; the gas storage tank is connected with the gas-liquid separator through a gas flowmeter; the gas-liquid separator is connected with the back pressure valve, and the back pressure valve is connected with the first mining steel pipe and the second mining steel pipe; the vacuum pump is connected with the gas flowmeter.
7. The assay device of claim 6, wherein: the first valve, the second valve, the third valve, the fourth valve, the fifth valve, the sixth valve, the seventh valve, the eighth valve, the ninth valve, the tenth valve, the eleventh valve, the twelfth valve, the thirteenth valve, the fourteenth valve, the fifteenth valve and the sixteenth valve realize the opening and closing of each pipeline; and the gas pressure controller, the gas flowmeter, the first balance, the second balance, the shaft pressure controller, the telescopic shaft, the pressure sensor and the temperature sensor are all connected with the computer.
8. The assay device of claim 1, wherein: the whole body formed by the upper cover of the reaction kettle, the reaction kettle and the lower bottom of the reaction kettle is positioned in a constant-temperature gas bath.
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